Sulfonated aliphatic-aromatic copolyesters

ABSTRACT

A sulfonated copolyester of the reaction product of: (a) one or more aromatic dicarboxylic acids or an ester thereof; (b) one or more aliphatic dicarboxylic acids or an ester thereof; (c) one or more sulfonated compound; and (d) isosorbide. The polyesters are useful to form articles of increased biodegradability.

FIELD OF THE INVENTION

This invention relates to sulfonated copolyesters that can exhibit animproved rate of biodegradation more amenable to solid waste disposal.The invention also relates to methods of making and using thecopolyesters.

BACKGROUND OF THE INVENTION

The inadequate treatment of municipal solid waste deposited in landfillsand the increasing addition of nondegradable materials, includingplastics, to municipal solid waste streams are combining to drasticallyreduce the number of landfills available and to increase the costs ofmunicipal solid waste disposal. While recycling of reusable componentsof the solid waste is desirable in many instances, the costs ofrecycling and the infrastructure required to recycle materials issometimes prohibitive. In addition, there are some products, which donot easily fit into the framework of recycling. One alternative approachis the composting of non-recyclable solid waste—a recognized and growingmethod to reduce solid waste volume for landfilling. Products from thecomposted waste can be used to improve the fertility of fields andgardens. However, one of the limitations to marketing such compostedproduct is the visible contamination by undegraded plastic, such as filmor fiber fragments.

Polymer components are sought that are useful in disposable products andwhich are degraded into less contaminating forms under the conditionstypically existing in waste composting processes. It is furtherdesirable to provide disposable components, which will not only degradeaerobically/anaerobically in composting, but will continue to degrade inthe soil or landfill.

Polyesters have been considered for biodegradable articles and end-usesin the past. These biodegradable polyesters can be characterized asbelonging to three general classes; aliphatic polyesters (polyestersderived solely from aliphatic dicarboxylic acids), aliphatic-aromaticpolyesters (polyesters derived from a mixture of aliphatic dicarboxylicacids and aromatic dicarboxylic acids), and sulfonated polyestersderived from a mixture of aliphatic dicarboxylic acids and aromaticdicarboxylic acids and, in addition, incorporating a sulfonated monomer,such as the salts of 5-sulfoisophthalic acid.

A shortcoming of the above mentioned polyesters is that they often donot provide a composition which combines both high temperaturecharacteristics, which are required by many enduses, such as dualovenable food trays and the like, with a high rate of biodegradation, asdesired to avoid the filling of landfills. It has been generally foundthat the biodegradation rate of the polyester may be enhanced throughthe addition of greater amounts of aliphatic dicarboxylic acids. At thesame time, it has been generally found that the incorporation of suchaliphatic dicarboxylic acids into a polyester composition tends todegrade the thermal properties of the polyester composition, as measuredthrough the glass transition temperature, (Tg).

Isosorbide has been incorporated as a monomer into aliphatic andaromatic polyesters. A recent review is found in Hans R. Kricheldorf,et. al., J. M. S.-Rev. Macromol. Chem. Phys., C37(4), pp. 599-631(1997). However it is generally believed that secondary alcohols such asisosorbide have poor reactivity and are sensitive to acid-catalyzedreactions.

One skilled in the art was thus confronted by three distinct art areas;(i) the sulfonated aliphatic-aromatic polyesters, which suffered fromrelatively low thermal properties, such as glass transitiontemperatures; (ii) the aliphatic isosorbide polyester art, whichsuffered from low molecular weights and thermal properties; and (iii)the aromatic isosorbide polyester art, which suffered from a lowbiodegradation rate.

SUMMARY OF THE INVENTION

The present invention has surprisingly found that the sulfonatedaliphatic-aromatic isosorbide copolyesters of the present inventioncombine good molecular weight and thermal properties with improvedbiodegradability.

The present invention provides a sulfonated copolyester comprising thepolymerization product of:

(a) one or more aromatic dicarboxylic acids or an ester thereof,

(b) one or more aliphatic dicarboxylic acids or an ester thereof;

(c) one or more sulfonated compound; and

(d) isosorbide.

The sulfonated aliphatic-aromatic copolyesters which incorporateisosorbide of the present invention are found to often avoid many of theshortcomings found in the art. The polymers of the invention can providea combination of a higher biodegradation rate with higher thermalproperties than found in the art.

Further objects, features and advantages of the invention will becomeapparent form the detailed description that follows.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The copolyesters of the present invention include isosorbide, which isthe diol 1,4:3,6-dianhydro-D-sorbitol. Isosorbide is readily made fromrenewable resources, such as sugars and starches. For example,isosorbide can be made from D-glucose by hydrogenation followed byacid-catalyzed dehydration. The preparation of isosorbide is knownwithin the literature in, for example, G. Fleche, et. al.,Starch/Starke, 38(1), pp. 26-30 (1986).

The terms glycol, diol and dihydric alcohol as used herein refer tosimilar general compositions of a primary, secondary or tertiary alcoholcontaining two hydroxyl groups and can be used interchangeably. The termglycol is more often used in the art to characterize low molecularweight alcohols such as ethylene glycol and propylene glycol. Diol anddihydric alcohol are typically applied to higher molecular weightalcohols, including polymeric diols.

Any aromatic dicarboxylic acid known in the art can be used. Usefularomatic dicarboxylic acids include unsubstituted and substitutedaromatic dicarboxylic acids and the lower alkyl (C₁-C₆) esters ofaromatic dicarboxylic acids; e.g., having from 8 carbons to 20 carbons.Examples of useful diacid moieties include those derived fromterephthalates, isophthalates, naphthalates, and bibenzoates. Specificexamples of useful aromatic dicarboxylic acid components includeterephthalic acid, dimethyl terephthalate, isophthalic acid, dimethylisophthalate, 2,6-napthalene dicarboxylic acid,dimethyl-2,6-naphthalate, 2,7-naphthalenedicarboxylic acid,dimethyl-2,7-naphthalate, 3,4′-diphenyl ether dicarboxylic acid,dimethyl-3,4′diphenyl ether dicarboxylate, 4,4′-diphenyl etherdicarboxylic acid, dimethyl-4,4′-diphenyl ether dicarboxylate,3,4′-diphenyl sulfide dicarboxylic acid, dimethyl-3,4′-diphenyl sulfidedicarboxylate, 4,4′-diphenyl sulfide dicarboxylic acid,dimethyl-4,4′-diphenyl sulfide dicarboxylate, 3,4′-diphenyl sulfonedicarboxylic acid, dimethyl-3,4′-diphenyl sulfone dicarboxylate,4,4′-diphenyl sulfone dicarboxylic acid, dimethyl-4,4′-diphenyl sulfonedicarboxylate, 3,4′-benzophenonedicarboxylic acid,dimethyl-3,4′-benzophenonedicarboxylate, 4,4′-benzophenonedicarboxylicacid, dimethyl-4,4′-benzophenonedicarboxylate, 1,4-naphthalenedicarboxylic acid, dimethyl-1,4-naphthalate, 4,4′-methylene bis(benzoicacid), dimethyl-4,4′-methylenebis(benzoate), and the like and mixturesof two or more thereof. Preferably, the aromatic dicarboxylic acidcomponent is derived from terephthalic acid, dimethyl terephthalate,isophthalic acid, dimethyl isophthalate, 2,6-naphthalene dicarboxylicacid, dimethyl-2,6-naphthalate, or mixtures of two or more thereof.

Any aliphatic dicarboxylic acid known in the art can be used within thepresent invention. Useful aliphatic dicarboxylic acid components includeunsubstituted (C₁-C₆), or substituted; linear, branched, or cyclicaliphatic dicarboxylic acids, and the lower alkyl esters thereof,preferably having 2-36 carbon atoms. Examples of useful aliphaticdicarboxylic acid components include, oxalic acid, dimethyl oxalate,malonic acid, dimethyl malonate, succinic acid, dimethyl succinate,methylsuccinc acid, glutaric acid, dimethyl glutarate, 2-methylglutaricacid, 3-methylglutaric acid, adipic acid, dimethyl adipate,3-methyladipic acid, 2,2,5,5-tetramethylhexanedioic acid, pimelic acid,suberic acid, azelaic acid, dimethyl azelate, sebacic acid,1,11-undecanedicarboxylic acid, 1,10-decanedicarboxylic acid,undecanedioic acid, 1,12-dodecanedicarboxylic acid, hexadecanedioicacid, docosanedioic acid, tetracosanedioic acid, dimer acid,1,4-cyclohexanedicarboxylic acid, dimethyl-1,4-cyclohexanedicarboxylate,1,3-cyclohexanedicarboxylic acid, dimethyl-1,3-cyclohexanedicarboxylate,1,1-cyclohexanediacetic acid, and the like and mixtures of two or morethereof. Preferred aliphatic acids or esters include succinic acid,dimethyl succinate, glutaric acid, dimethyl glutarate, adipic acid,demethyl adipate and dimer acid.

The copolyester polymer of the invention contains sulfo groups, asdescribed, for example, by Griffing et. al., in U.S. Pat. No. 3,018,272,the disclosure of which is hereby incorporated by reference. The sulfogroups may be introduced in any desired manner, e.g., in aliphatic oraromatic monomers such as sulfonated aliphatic or aromatic dicarboxylicacids or may be introduced as end-groups by including monofunctionalcomponents containing a sulfonic acid moiety as a substituent. Anexample of an aliphatic sulfonate component include the metal salts ofsulfosuccinic acid. Specific examples of aromatic sulfonate componentsthat can be used as end-groups include the metal salts of 3-sulfobenzoicacid, 4-sulfobenzoic acid and 5-sulfosalicylic acid. Preferred aresulfonate components whereby the sulfonate salt group is attached to anaromatic dicarboxylic acid. The aromatic nucleus may be benzene,naphthalene, diphenyl, oxydiphenyl, sulfonyldiphenyl, methylenediphenyl,or the like. Preferably, the sulfonate monomer is the residue of asulfonate-substituted phthalic acid, terephthalic acid, isophthalic acidor 2,6-naphthalenedicarboxylic acid. Most preferably, the sulfonatecomponent is a metal salt of 5-sulfoisophthalic acid or the lower alkyl(C₁-C₆) esters of 5-sulfoisophthalate.

The metal salt may be formed from monovalent or polyvalent alkali metalions, alkaline earth metal ions, or other metal ions and the like. Thealkali metal ion is, for example, sodium, potassium or lithium. Alkalineearth metals such as magnesium are also useful. Other useful metal ionsinclude the transition metal ions, such as zinc, cobalt, or iron Themultivalent metal ions may be used when an increase in the meltviscosity of the sulfonated aliphatic-aromatic copolyesters is desired.End-use examples where such melt viscosity enhancements may prove usefulare melt extrusion coatings, melt blown containers or film, and foam. Aslittle as 0.1 mole percent of the sulfo group contributes significantlyto the degradability characteristics of the resultant films or coatings.Preferably, the sulfo group is in the range of about 0.5 to about 5 molepercent level. However, higher levels of the sulfo group, for examplefrom about 7 to about 10 mole percent, would tend to make the polyesterresins of the present invention water sensitive and dispersible orsoluble in water-based solvent systems, and hence can be used when suchproperties are desired.

The polymer can be formed with an optional glycol. Any glycol known inthe art can be used as the optional dihydric alcohol of the invention.Examples include unsubstituted or substituted; straight chain, branched,cyclic aliphatic, aliphatic-aromatic, or aromatic diols having e.g.,from 2 carbon atoms to 36 carbon atoms and poly(alkylene ether) glycolswith molecular weights preferably between about 250 to about 4,000.Specific examples of the useful glycol component include ethyleneglycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol,1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol,1,16-hexadecanediol, dimer diol,4,8-bis(hydroxymethyl)-tricyclo[5.2.1.0/2.6]decane,1,4-cyclohexanedimethanol, di(ethylene glycol), tri(ethylene glycol),poly(ethylene ether) glycols, poly(butylene ether) glycols and the likeand mixtures of two or more. Preferred dihydric alcohols includeethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol andpoly(ethylene ether) glycols.

The polymer may be formed from an optional polyfunctional branchingagent, of which can include any material with three or more carboxylicacid functions, hydroxy functions or a mixture thereof. Specificexamples of useful polyfunctional branching agent component include1,2,4-benzenetricarboxylic acid (trimellitic acid),trimethyl-1,2,4-benzenetricarboxylate, 1,2,4-benzenetricarboxylicanhydride (trimellitic anhydride), 1,3,5-benzenetricarboxylic acid,1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid),1,2,4,5-benzenetetracarboxylic dianhydride (pyromellitic anhydride),3,3′,4,4′-benzophenonetetracarboxylic dianhydride,1,4,5,8-naphthalenetetracarboxylic dianhydride, citric acid,tetrahydrofuran-2,3,4,5-tetracarboxylic acid,1,3,5-cyclohexanetricarboxylic acid, pentaerythritol,2-(hydroxymethyl)1,3-propanediol, 2,2-bis(hydroxymethyl)propionic acid,and the like and mixtures of two or more thereof. The polyfunctionalbranching agent may be included when higher resin melt viscosity isdesired for specific enduses. Examples of such end-uses include meltextrusion coatings, melt blown films or containers, foam and the like.

To give the desired physical properties, the sulfonatedaliphatic-aromatic copolyesters which incorporate isosorbide of thepresent invention should preferably have an inherent viscosity, which isan indicator of molecular weight, of at least equal to or greater thanabout 0.15. More desirably, the inherent viscosity, (IV), of thealiphatic-aromatic copolyesters which include isosorbide will be equalto or greater than about 0.35 dL/g. IV is measured on a 0.5 percent(weight/volume) solution of the copolyester in a 50:50 (weight) solutionof trifluoroacetic acid:dichloromethane solvent system at roomtemperature. Even higher inherent viscosity's are desirable for manyother applications, such as films, bottles, sheet, molding resin, andthe like. The polymerization conditions may be adjusted to obtain thedesired inherent viscosity's up to at least about 0.5 and desirablyhigher than 0.65 dL/g. Further processing of the copolyester may achieveinherent viscosity's of 0.7, 0.8, 0.9, 1.0, 1.5, 2.0 dL/g and evenhigher.

The polyesters of the present invention can be prepared by conventionalpolycondensation techniques. The product compositions may vary somewhatbased on the method of preparation used, particularly in the amount ofdiol that is present within the polymer. These methods include thereaction of the diol monomers with the acid chlorides. For example, acidchlorides of the aromatic dicarboxylic acid component and the aliphaticdicarboxylic acid component may be combined with the isosorbide and theother glycol component in a solvent, such as toluene, in the presence ofa base, such as pyridine, which neutralizes the hydrochloric acid as itis produced. Such procedures are known. See, for example, R. Storbeck,et. al., J. Appl. Polymer Science, Vol. 59, pp. 1199-1202 (1996). Otherwell known variations using acid chlorides may also be used, such as aninterfacial polymerization method, or the monomers may simply be stirredtogether while heating.

When the polymer is made using acid chlorides, the ratio of the monomerunits in the product polymer is about the same as the ratio of reactingmonomers. Therefore, the ratio of monomers charged to the reactor isabout the same as the desired ratio in the product. An approximatelystoichiometric equivalent of the diol components and the diacidcomponents can be used to obtain a higher molecular weight polymer.

Preferably, the copolyesters are produced through a melt polymerizationmethod. In the melt polymerization method, the aromatic dicarboxylicacid component, (either as acids, esters, or mixtures thereof), thealiphatic dicarboxylic acid component, (either as acids, esters, ormixtures thereof), the isosorbide, the sulfonated component, the otheroptional glycol component and optionally the polyfunctional branchingagent, are combined in the presence of a catalyst at a temperature highenough such that the monomers combine to form esters and diesters, thenoligomers, and finally polymers. The polymeric product at the end of thepolymerization process is a molten product. Generally, the diolcomponent and the isosorbide are volatile and distill from the reactoras the polymerization proceeds. Such procedures are known. See, forexample, Charbonneau, et. al., in U.S. Pat. No. 6,063,464 and thereferences cited therein.

The melt process conditions of the present invention, particularly theamounts of monomers used, depend on the polymer composition that isdesired. The amount of isosorbide, the other glycol or dihydric alcoholcomponent, aromatic dicarboxylic acid component, aliphatic acidcomponent, sulfonated component, and branching agent are desirablychosen so that the final polymeric product contains the desired amountsof the various monomer units, desirably with approximately equimolaramounts of monomer units derived from the respective diol and diacidcomponents. Because of the volatility of some of the monomers,especially some of the glycol components and isosorbide, and dependingon such variables as whether the reactor is sealed, (i.e.; is underpressure), the polymerization temperature ramp rate, and the efficiencyof the distillation columns used in synthesizing the polymer, some ofthe monomers may need to be included in excess at the beginning of thepolymerization reaction and removed by distillation as the reactionproceeds. This is particularly true of the glycol component and ofisosorbide.

The amount of monomers to be charged to a particular reactor is readilydetermined by a skilled practitioner, but often will be in the rangesbelow. Excesses of the diacid, diol, and isosorbide are often desirablycharged, and the excess diacid, diol and isosorbide is desirably removedby distillation or other means of evaporation as the polymerizationreaction proceeds. Isosorbide is desirably charged at a level 20 to 100percent greater than the desired incorporation level in the finalpolymer. The other optional glycol component is desirably charged at alevel 0 to 100 percent greater than the desired incorporation level inthe final product. For examples of the other glycol component which arevolatile under the polymerization conditions, such as ethylene glycol,1,3-propanediol, or 1,4-butanediol, 30 to 100 percent excesses aredesirably charged. For less volatile examples of the other glycolcomponent, such as dimer diol, no excesses need be desirably charged.Typically the diacid and sulfonated components are not added in excessesbecause they are not typically volatile. This, depends on the chemicalnature and volatility of the specific materials chosen. Thus, dependingon the specific material used, excess of diacid or sulfonated componentcan be used.

The ranges given below for the monomers vary because of the widevariation in the monomer loss during polymerization, depending on theefficiency of distillation columns and other kinds of recovery andrecycle systems and the like. Exact amounts of monomers that are chargedto a specific reactor to achieve a specific composition are readilydetermined by a skilled practitioner.

While the copolyesters can include any amount of the monomer, generallyabout 98 to about 20 mole percent, preferably about 90 to about 40 molepercent, more preferably about 80 to about 50 mole percent of aromaticdicarboxylic acid (based on total dicarboxylic acids); about 2 to about80 mole percent, preferably about 10 to about 60 mole percent, morepreferably about 20 to about 50 mole percent of aliphatic dicarboxylicacid (based on total dicarboxylic acids); about 0.1 to about 10 molepercent, preferably about 0.3 to about 5.0 mol percent, more preferablyabout 0.5 to about 2.5 mole percent of sulfonate compound (based ontotal glycols or total dicarboxylic acids, depending on the chemicalfunctionality of the used sulfonate component, e.g., if the sulfonatecomponent is dimethyl-5-sulfo-isophthalate, sodium salt it is based onacids); about 100 to about 1 mole percent, preferably about 50 to about2 mole percent, more preferably about 25 to about 5 mole percent ofisosorbide (based on total glycols (diols)); and 0 to about 99 molepercent, preferably about 50 to about 98 mole percent, more referablyabout 75 to about 95 mole percent of other glycol (based on totalglycols (diols)); and 0 to about 5 mole percent, preferably 0.5 to about2.5 mole percent, more preferably about 1 to about 1.0 mole percent ofpolyfunctional branching agent (based on total glycols or totaldicarboxylic acids, depending on the chemical functionality of the usedpolyfunctional branching agent); are used.

These ranges are for monomers incorporated into the polymer. For thereasons discussed above, the amount of monomer required to achieve theincorporation level desired will vary widely based on the nature ofmonomer chosen. This disparity between added monomer and monomer levelincorporated is further demonstrated within the examples. For example,the incorporation rate of isosorbide can be at 50%, and other glycols,such as ethylene glycol, is typically added in 30 to 100 percentexcesses.

In the polymerization process, the monomers are combined, and are heatedgenerally with mixing with a catalyst or catalyst mixture to atemperature, generally in the range of 230° C. to about 300° C.,desirably 250° C. to 295° C. The exact conditions and the catalystsdepend, for example, on whether the diacids are polymerized as trueacids or as dimethyl esters. The catalyst may be included initially withthe reactants, and/or may be added one or more times to the mixture asit is heated. The catalyst used may be modified as the reactionproceeds. The heating and stirring are continued for a sufficient timeand to a sufficient temperature, generally with removal by distillationof excess reactants, to yield a molten polymer having a high enoughmolecular weight to be suitable for making fabricated products.

Any desired catalyst may be used. Catalysts that may be used includesalts of Li, Ca, Mg, Mn, Zn, Pb, Sb, Sn, Ge, and Ti, such as acetatesalts and oxides, including glycol adducts, and Ti alkoxides. These aregenerally known in the art, and the specific catalyst or combination orsequence of catalysts used may be readily selected by a skilledpractitioner. The preferred catalyst and preferred conditions differdepending on, for example, whether the diacid monomer is polymerized asthe free diacid or as a dimethyl ester and the chemical identity of theother optional glycol component.

The monomer composition of the polymer is chosen for specific uses andfor specific sets of properties. For uses where a partially crystallinepolymer is desired, as for example food and beverage containers, such ashot fill or cold fill bottles, fibers, and films, the polymer willgenerally have a monomer composition in the range of about 1.0 to 10.0mole percent, preferably about 1 to about 5 mole percent of isosorbidemoieties, based on total glycol.

For applications where it is desirable to have an amorphous polymer,such as would be the case to make transparent optical articles orsolvent soluble copolyesters, the amount of isosorbide moiety isgenerally greater than about 2.0 mole percent, again based on totalglycol.

Polymers can be made by the melt condensation process described abovehaving adequate inherent viscosity for many applications. Solid statepolymerization may be used to achieve even higher inherent viscosity's(molecular weights).

The product made by melt polymerization, after extruding, cooling andpelletizing, may be essentially noncrystalline. Noncrystalline materialcan be made semicrystalline by heating it to a temperature above theglass transition temperature for an extended period of time. Thisinduces crystallization so that the product can then be heated to ahigher temperature to raise the molecular weight.

The polymer may also be crystallized prior to solid state polymerizationby treatment with a relatively poor solvent for polyesters which inducescrystallization. Such solvents reduce the glass transition temperature(Tg) allowing for crystallization. Solvent induced crystallization isknown for polyesters and is described in U.S. Pat. Nos. 5,164,478 and3,684,766.

The semicrystalline polymer can be subjected to solid statepolymerization by placing the pelletized or pulverized polymer into astream of an inert gas, usually nitrogen, or under a vacuum of about 1Torr, at an elevated temperature, but below the melting temperature ofthe polymer for an extended period of time.

The present copolyesters are generally substantially biodegradablecompared to other copolyesters known in the art. For example, whencompared with comparable aromatic isosorbide polyesters known within theart which do not incorporate either aliphatic dicarboxylic acidcomponent of the present invention or the sulfonate compound of thepresent invention, the sulfonated aliphatic-aromatic copolyesters whichincorporate isosorbide of the present invention often have abiodegradation rate at least twice that found for the comparablearomatic isosorbide polyesters of the art, as can be measured by thebelow mentioned ISO 14855 composting method. Also, the sulfonatedaliphatic-aromatic copolyesters which incorporate isosorbide of thepresent invention often have greater thermal properties, as can bemeasured by the glass transition temperature, (Tg), crystalline meltingpoint, (T m), or heat deflection temperature, (HDT), then found for thecorresponding aliphatic isosorbide polyesters and sulfonatedaliphatic-aromatic polyesters of the art.

Some of the above described sulfonated aliphatic-aromatic copolyesterswhich incorporate isosorbide have both biodegradable and solventsolubility in common, non-halogenated, polar solvents. Examples of thenon-halogenated, polar solvents include tetrahydrofuran, dimethylacetamide, dimethyl formamide, N-methylpyrollidone, dimethylsulfoxide,and the like. Some of the aliphatic-aromatic copolyesters whichincorporate isosorbide of the current invention are readily soluble insaid solvents and the resulting polymer solutions provide clear films.

The copolyesters of the present invention may be used with additivesknown within the art. Such additives may include thermal stabilizers,for example, phenolic antioxidants, secondary thermal stabilizers, forexample, thioethers and phosphites, UV absorbers, for examplebenzophenone- and benzotriazole-derivatives, UV stabilizers, forexample, hindered amine light stabilizers (HALS), and the like. Theadditives may further include plasticizers, processing aides, flowenhancing additives, lubricants, pigments, flame retardants, impactmodifiers, nucleating agents to increase crystallinity, antiblockingagents such as silica and the like. In addition, the compositions of thepresent invention may be filled with, for example, wood flour, gypsum,wollastonite, chalk, kaolin, clay, silicon oxide, calcium terephthalate,aluminum oxide, titanium oxide, calcium phosphate, lithium fluoride,cellulose, starch, chemically modified starch, thermoplastic starch,calcium carbonate, reinforcing agents, such as glass, and the like. Thecompositions of the present invention may also find use as a componentof a polymer blend with other polymers, such as cellulose ethers,thermoplastic starch, poly(vinyl alcohol), and the like. Generally anyadditive or filler of the art can be used with the copolyesters of thepresent invention.

The sulfonated aliphatic-aromatic copolyesters which incorporateisosorbide of the present invention are useful within a wide variety ofshaped biodegradable articles. The copolyesters may be solution or meltprocessed to form coatings, films and the like. Coatings may be producedby coating a substrate with polymer solutions of the copolyestersfollowed by drying, by coextruding the copolyesters with othermaterials, or by melt coating a preformed substrate with the polyestersof the present invention. The coatings derived from the copolyesters ofthe present invention have utility as barriers to moisture, oxygen,carbon dioxide and the like. The coatings derived from the copolyestersof the present invention also are useful as adhesives. Films of thecopolyesters of the present invention may be produced by any known artmethod, including, for example, solution or melt casting.

Shaped articles include films, sheets, fibers, melt blown containers,molded parts, such as cutlery, foamed parts, polymeric melt extrusioncoatings onto substrates, polymeric solution coatings onto substrates,and the like. The copolyesters may be solution or melt processed to formcoatings, films and the like. Films of the copolyesters of the presentinvention may be produced by any known art method, including, forexample, solution or melt casting.

Film or sheets are made from the polymer of the invention by any processknown in the art. The difference between a film and a sheet is thethickness, but there is no set industry standard as to when a filmbecomes a sheet.

For purposes of this invention, a film is less than or equal to about0.25 mm (10 mils) thick, preferably between about 0.025 mm and 0.15 mm(1 mil and 6 mils). However, thicker films can be formed up to athickness of about 0.50 mm (20 mils).

The film of the present invention can be formed by either solutioncasting or extrusion as known in the art. Extrusion is particularlypreferred for formation of “endless” products, such as films and sheets,which emerge as a continuous length. In extrusion, the polymericmaterial, whether provided as a molten polymer or as plastic pellets orgranules, is fluidized and homogenized. This mixture is then forcedthrough a suitably shaped die to produce the desired cross-sectionalfilm shape. The extruding force may be exerted by a piston or ram (ramextrusion), or by a rotating screw (screw extrusion), which operateswithin a cylinder in which the material is heated and plasticized andfrom which it is then extruded through the die in a continuous flow.Single screw, twin screw, and multi-screw extruders may be used as knownin the art. Different kinds of die are used to produce differentproducts, such as blown film (formed by a blow head for blownextrusions), sheets and strips (slot dies) and hollow and solid sections(circular dies). In this manner, films of different widths and thicknessmay be produced, and, in some cases, such as when film is used as acoating, it may be extruded directly onto the object to be coated. Forexample, wires and cables can be sheathed directly with polymeric filmsextruded from oblique heads. As a further example, laminated papercoatings can be produced by melt extruding the polymer directly ontopaperboard. After extrusion, the polymeric film is taken up on rollers,cooled and taken off by means of suitable devices which are designed toprevent any subsequent deformation of the film.

Using extruders as known in the art, film can be produced by extruding athin layer of polymer over chilled rolls and then further drawing downthe film to size by tension rolls. Preferably, the finished film is lessthan or equal to about 0.25 mm thick. Blown film, which is generallystronger, tougher, and made more rapidly than cast film, is made byextruding a tube. In producing blown film, the melt flow is turnedupward from the extruder and fed through an annular die. As this tubeleaves the die, internal pressure is introduced through the die mandrelwith air, which expands the tube from about 1.5 to about 2.5 times thedie diameter and simultaneously draws the film, causing a reduction inthickness. The resulting sleeve is subsequently slit along one side,making a larger film width than could be conveniently made via the castfilm method. In extrusion coating, the substrate (paper, foil, fabric,polymeric film, and the like) is compressed together with the extrudedpolymeric melt by pressure rolls so that the polymer impregnates thesubstrate for maximum adhesion.

For manufacturing large quantities of film, a sheeting calendar can beemployed. The rough film is fed into the gap of the calendar, a machinecomprising a number of heatable parallel cylindrical rollers whichrotate in opposite directions and spread out the polymer and stretch itto the required thickness. The last roller smoothes the film thusproduced. If the film is required to have a textured surface, the finalroller is provided with an appropriate embossing pattern. Alternatively,the film may be reheated and then passed through an embossing calendar.The calendar is followed by one or more cooling drums. Finally, thefinished film is reeled up.

Alternatively, as mentioned previously, a supporting material may becoated directly with a film. For example, textile fabrics, paper,cardboard, metals, various building materials and the like, may becoated directly with the polyester polymer for the purpose of electricalinsulation, protection against corrosion, protection against the actionof moisture or chemicals, impermeability to gases and liquids, orincreasing the mechanical strength. One process to achieve this isreferred to as melt extrusion of the polymeric melt onto a substrate.Coatings are applied to textiles, foil, and other sheet materials bycontinuously operating spread-coating machines. A coating knife, such asa “doctor knife”, ensures uniform spreading of the coating materials (inthe form of solution, emulsions, or dispersions in water or an organicmedium) on the supporting material, which is moved along by rollers. Thecoating is then dried. Alternatively, when the coating is applied to thesupporting material in the form of a polymeric film, the process iscalled laminating.

Metal articles of complex shapes can also be coated with the polymericfilm by the whirl sintering process. The articles, heated to above themelting point of the polymer, are introduced into a fluidized bed ofpowdered polymer wherein the polymer particles are held in suspension bya rising stream of air, thus depositing a coating on the metal bysintering.

Extruded films may also be used as the starting material for otherproducts. For example, the film may be cut into small segments for useas feed material for other processing methods, such as injectionmolding.

The extrusion process can be combined with a variety of post-extrudingoperations for expanded versatility. Such post-forming operationsinclude altering round to oval shapes, blowing the film to differentdimensions, machining and punching, biaxial stretching and the like, asknown to those skilled in the art.

The polymeric film of the invention may be combined with other polymericmaterials during extrusion and/or finishing to form laminates ormultilayer films with improved characteristics, such as water vaporresistance. In particular, the polymeric film of the invention may becombined with one or more of the following: poly(ethylene terephthalate)(PET), aramid, polyethylene sulfide (PES), polyphenylene sulfide (PPS),polyimide (PI), polyethylene imine (PEI), poly(ethylene naphthalate)(PEN), polysulfone (PS), polyether ether ketone (PEEK), olefins,polyethylene, poly(cyclic olefins), cellulose, and cyclohexylenedimethylene terephthalate, for example. A multilayer or laminate filmmay be made by any method known in the art, and may have as many as fiveor more separate layers joined together by heat, adhesive and/or tielayer, as known in the art.

A film may also be made by solution casting, which produces moreconsistently uniform gauge film than that made by melt extrusion.Solution casting comprises dissolving polymeric granules, powder or thelike in a suitable solvent with any desired formulant, such as aplasticizer or colorant. The solution is filtered to remove dirt orlarge particles and cast from a slot die onto a moving belt, preferablyof stainless steel, dried, whereon the film cools. The extrudatethickness is five to ten times that of the finished film. The film maythen be finished in a like manner to the extruded film.

Regardless of how the film is formed, it is desirably subjected tobiaxial orientation by stretching in both the machine and transversedirection after formation. The machine direction stretch is initiated informing the film simply by rolling out and taking up the film. Thisinherently stretches the film in the direction of takeup, orienting someof the fibers. Although this strengthens the film in the machinedirection, it allows the film to tear easily in the direction at rightangles because all of the fibers are oriented in one direction.

Biaxial stretching orients the fibers parallel to the plane of the film,but leaves the fibers randomly oriented within the plane of the film.This provides superior tensile strength, flexibility, toughness andshrinkability, for example, in comparison to non-oriented films. It isdesirable to stretch the film along two axes at right angles to eachother. This increases tensile strength and elastic modulus in thedirections of stretch. It is most desirable for the amount of stretch ineach direction to be roughly equivalent, thereby providing similarproperties or behavior within the film when tested from any direction.However, certain applications, such as those desiring a certain amountof shrinkage or greater strength in one direction over another, as inlabels or adhesive and magnetic tapes, will require uneven, or uniaxial,orientation of the fibers of the film.

The biaxial orientation may be obtained by any process known in the art.However, tentering is preferred, wherein the material is stretched whileheating in the transverse direction simultaneously with, or subsequentto, stretching in the machine direction.

Shrinkage can be controlled by holding the film in a stretched positionand heating for a few seconds before quenching. This heat stabilizes theoriented film, which then may be forced to shrink only at temperaturesabove the heat stabilization temperature.

The above process conditions and parameters for film making aredetermined by a skilled artisan for any given polymeric composition anddesired application.

The properties exhibited by a film will depend on several factorsincluding the polymeric composition, the method of forming the polymer,the method of forming the film, and whether the film was treated forstretch or biaxially oriented. These factors affect many properties ofthe film, such as shrinkage, tensile strength, elongation at break,impact strength, dielectric strength and constant, tensile modulus,chemical resistance, melting point, heat deflection temperature, and thelike.

The film properties may be further adjusted by adding certain additivesand fillers to the polymeric composition, such as colorants, dyes, UVand thermal stabilizers, antioxidants, plasticizers, lubricantsantiblock agents, slip agents, and the like, as recited above.Alternatively, the copolyesters of the present invention may be blendedwith one or more other polymers, such as starch, to improve certaincharacteristics.

The biodegradable films of the present invention can be used e.g., inpackaging, especially of foodstuff, adhesives, insulators, capacitors,photographic development, x-ray development, and as laminates. For manyof these uses, the heat resistance of the film is an important factor.Thus, the higher melting point and Tg of the present polyesters aredesirable.

The present invention also includes biodegradable shaped articles in theform of sheets produced from sulfonated aliphatic-aromatic copolyesters.

Biodegradable polymeric sheets have a variety of uses, such as insignage, glazings, thermoforming articles, displays and displaysubstrates, for example. For many of these uses, the heat resistance ofthe sheet is an important factor. Therefore, a higher melting point andglass transition temperature are desirable to provide better heatresistance and greater stability. Further, it is desired that thesesheets have ultraviolet (UV) and scratch resistance, good tensilestrength, high optical clarity, and a good impact strength, particularlyat low temperatures.

The copolyesters of the present invention may be formed by one of theabove methods, or by any other method known in the art, they may beformed into sheets directly from the polymerization melt. In thealternative, the copolyester may be formed into an easily handled shape(such as pellets) from the melt, which may then be used to form a sheet.The sheet of the present invention can be used for forming signs,glazings (such as in bus stop shelters, sky lights or recreationalvehicles), displays, automobile lights and in thermoforming articles,for example.

The difference between a sheet and a film is the thickness, but there isno set industry standard as to when a film becomes a sheet. For purposesof this invention, a sheet is greater than about 0.25 mm (10 mils)thick, preferably between about 0.25 mm and 25 mm, more preferably fromabout 2 mm to about 15 mm, and even more preferably from about 3 mm toabout 10 mm. In a preferred embodiment, the sheets of the presentinvention have a thickness sufficient to cause the sheet to be rigid,which generally occurs at about 0.50 mm and greater. However, sheetsgreater than 25 mm, and thinner than 0.25 mm may be formed.

Sheets may be formed by any process known in the art, such as extrusion,solution casting or injection molding. The parameters for each of theseprocesses can be determined by one of ordinary skill in the artdepending upon viscosity characteristics of the copolyester and thedesired thickness of the sheet.

The sheet of the present invention is preferably formed by eithersolution casting or extrusion. Extrusion is particularly preferred forformation of “endless” products, such as films and sheets, which emergeas a continuous length. For example, see applications WO 96/38282 and WO97/00284, which describe the formation of crystallizable sheets by meltextrusion.

In extrusion, the polymeric material, whether provided as a moltenpolymer or as plastic pellets or granules, is fluidized and homogenized.This mixture is then forced through a suitably shaped die to produce thedesired cross-sectional sheet shape. The extruding force may be exertedby a piston or ram (ram extrusion), or by a rotating screw (screwextrusion), which operates within a cylinder in which the material isheated and plasticized and from which it is then extruded through thedie in a continuous flow. Single screw, twin screw, and multi-screwextruders may be used as known in the art. Different kinds of die areused to produce different products, such as sheets and strips (slotdies) and hollow and solid sections (circular dies). In this manner,sheets of different widths and thickness may be produced. Afterextrusion, the polymeric sheet is taken up on rollers, cooled and takenoff by suitable devices which are designed to prevent any subsequentdeformation of the sheet.

Using extruders as known in the art, a sheet can be produced byextruding a thin layer of polymer over chilled rolls and then furtherdrawing down the sheet to size by tension rolls. Preferably, thefinished sheet is greater than 0.25 mm thick.

For manufacturing large quantities of sheets, a sheeting calendar can beemployed. The rough film is fed into the gap of the calendar, a machinecomprising a number of heatable parallel cylindrical rollers whichrotate in opposite directions and spread out the polymer and stretch itto the required thickness. The last roller smoothes the sheet thusproduced. If the sheet is required to have a textured surface, the finalroller is provided with an appropriate embossing pattern. Alternatively,the sheet may be reheated and then passed through an embossing calendar.The calendar is followed by one or more cooling drums. Finally, thefinished sheet is reeled up.

The above extrusion process can be combined with a variety ofpost-extruding operations for expanded versatility. Such post-formingoperations include altering round to oval shapes, stretching the sheetto different dimensions, machining and punching, biaxial stretching andthe like, as known to those skilled in the art.

The polymeric sheet of the invention may be combined with otherpolymeric materials during extrusion and/or finishing to form laminatesor multilayer sheets with improved characteristics, such as water vaporresistance. These are discussed above with reference to films.

A sheet may also be made by solution casting as discussed above.

Further, sheets and sheet-like articles, such as discs, may be formed byinjection molding by any method known in the art.

Shrinkage can be controlled by holding the sheet in a stretched positionand heating for a few seconds before quenching. This heat stabilizes theoriented sheet, which then may be forced to shrink only at temperaturesabove the heat stabilization temperature.

The above process conditions and parameters for sheet making can bedetermined by a skilled artisan for any given polymeric composition anddesired application.

The properties exhibited by a sheet will depend on several factorsincluding the polymeric composition, the method of forming the polymer,the method of forming the sheet, and whether the sheet was treated forstretch or biaxially oriented. These factors affect many properties ofthe sheet, such as shrinkage, tensile strength, elongation at break,impact strength, dielectric strength and constant, tensile modulus,chemical resistance, melting point, heat deflection temperature, and thelike.

The sheet properties may be further adjusted by adding certain additivesand fillers to the polymeric composition, such as colorants, dyes, UVand thermal stabilizers, antioxidants, plasticizers, lubricantsantiblock agents, slip agents, and the like, as recited above.Alternatively, the copolyesters of the present invention may be blendedwith one or more other polymers, such as starch, to improve certaincharacteristics. Other polymers may be added to change suchcharacteristics as air permeability, optical clarity, strength and/orelasticity, for example.

The sheets of the present invention may be thermoformed by any knownmethod into any desirable shape, such as covers, skylights, shapedgreenhouse glazings, displays, food trays, and the like. Thethermoforming can be accomplished by heating the sheet to a sufficienttemperature and for sufficient time to soften the copolyester so thatthe sheet can be easily molded into the desired shape. In this regard,one of ordinary skill in the art can determine the optimal thermoformingparameters depending upon the viscosity and crystallizationcharacteristics of the polyester sheet.

A further specific aspect of the present invention includesbiodegradable shaped articles in the form of containers produced fromthe copolyesters the containers may be made by any method known in theart, such as extrusion, injection molding, injection blow molding,rotational molding, thermoforming of a sheet, and stretch-blow molding.

A preferred method for molding a container is stretch-blow molding. Inthis case, use may be made of any of the cold parison methods, in whicha preformed parison (generally made by injection molding) is taken outof the mold and then subjected to stretch blow molding in a separatestep. The hot parison method as known in the art may also be used,wherein the hot parison is immediately subjected to stretch blow moldingin the same equipment without complete cooling after injection moldingto make the parison. The parison temperature will vary based on thecomposition of the polymer to be used. Generally, parison temperaturesin the range from about 90° to about 160° C. are found useful. Thestretch blow molding temperature will also vary dependant on thematerial composition used, but a mold temperature of about 80° C. toabout 150° C. is generally found to be useful.

Containers of the invention may have any shape desirable, andparticularly include narrow-mouth bottles and wide-mouth bottles havingthreaded tops and a volume of about 400 mL to about 3 liters, althoughsmaller and larger containers may be formed.

The containers can be used in standard cold fill applications. For someof the compositions of the present invention, hot fill applications mayalso be used.

The containers of the invention are suitable for foods and beverages,and other solids and liquids. The containers are normally clear andtransparent, but can be modified to have color or to be opaque, ratherthan transparent, if desired, by adding colorants or dyes, or by causingcrystallization of the polymer, which results in opaqueness.

A further specific aspect of the present invention includesbiodegradable shaped articles in the form of fiber produced from thesulfonated aliphatic-aromatic copolyesters which incorporate isosorbide.

Polyester fibers are produced in large quantities for use in a varietyof applications. In particular, these fibers are desirable for use intextiles, particularly in combination with natural fibers such as cottonand wool. Clothing, rugs, and other items may be fashioned from thesefibers. Further, polyester fibers are desirable for use in industrialapplications due to their elasticity and strength. In particular, theyare used to make articles such as tire cords and ropes.

The term “fibers” as used herein is meant to include continuousmonofilaments, non-twisted or entangled multifilament yarns, stapleyarns, spun yarns, and non-woven materials. Such fibers may be used toform uneven fabrics, knitted fabrics, fabric webs, or any otherfiber-containing structures, such as tire cords.

The monomer composition of the copolyester of the present invention whenused in fiber is desirably chosen to result in a partially crystallinepolymer. The crystallinity is desirable for the formation of fibers,providing strength and elasticity. As first produced, the polyester ismostly amorphous in structure. In preferred embodiments, the polyesterpolymer readily crystallizes on reheating and/or extension of thepolymer.

Fibers are made from the polymer by any process known in the art.Generally, melt spinning is preferred. Melt spinning comprises heatingthe polymer to form a molten liquid, or melting the polymer against aheated surface. The molten polymer is forced through a spinneret with aplurality of fine holes. Upon contact with air or a non-reactive gasstream after passing through the spinneret, the polymer solution fromeach spinneret solidifies into filaments. The filaments are gatheredtogether downstream from the spinneret by a convergence guide, and maybe taken up by a roller or a plurality of rollers. This process allowsfilaments of various sizes and cross sections to be formed, includingfilaments having a round, elliptical, square, rectangular, lobed ordog-boned cross section, for example.

Following the extrusion and uptake of the fiber, the fiber is usuallydrawn, thereby increasing the crystallization and maximizing desirableproperties such as orientation along the longitudinal axis, whichincreases elasticity, and strength. The drawing may be done incombination with takeup by using a series of rollers, some of which aregenerally heated, as known in the art, or may be done as a separatestage in the process of fiber formation.

The polymer may be spun at speeds of from about 600 to 6000 meters perminute or higher, depending on the desired fiber size. For textileapplications, a fiber with a denier per filament of from about 0.1 toabout 100 is desired. Preferably, the denier is about 0.5 to 20, morepreferably 0.7 to 10. However, for industrial applications the fibershould be from about 0.5 to 100 denier per filament, preferably about1.0 to 10.0, most preferably 3.0 to 5.0 denier per filament. Therequired size and strength of a fiber can be readily be determined byone of ordinary skill in the art for any given application.

The resulting filmentary material is amenable to further processingthrough the use of additional processing equipment, or it may be useddirectly in applications requiring a continuous filament textile yam. Ifdesired, the filamentary material subsequently may be converted from aflat yam to a textured yarn through known false twist texturingconditions or other processes known in the art. In particular, it isdesirable to increase the surface area of the fiber to provide a softerfeel and to enhance the ability of the fibers to breathe, therebyproviding better insulation and water retention in the case of textiles,for example. The fibers may therefore be crimped or twisted by the falsetwist method, air jet, edge crimp, gear crimp, or stuffer box, forexample. Alternatively, the fibers may be cut into shorter lengths,called staple, which may be processed into yarn. A skilled artisan candetermine the best method of crimping or twisting based on the desiredapplication and the composition of the fiber.

After formation, the fibers are finished by any method appropriate tothe desired final use. In the case of textiles, this may include dyeing,sizing, or addition of chemical agents such as anitstatic agents, flameretardants, UV light stabilizers, antioxidants, pigments, dyes, stainresistants, antimicrobial agents and the like, which are appropriate toadjust the look and hand of the fibers. For industrial applications, thefibers may be treated to impart additional desired characteristics suchas strength, elasticity or shrinkage, for example.

The continuous filament fiber of the invention may be used either asproduced or texturized for use in a variety of applications such astextile fabrics for apparel and home furnishings, for example. Hightenacity fiber can be used in industrial applications such as highstrength fabrics, tarpaulins, sail cloth, sewing threads and rubberreinforcement for tires and V-belts, for example.

The staple fiber of the invention may be used to form a blend withnatural fibers, especially cotton and wool. In particular, the polyesteris a chemically resistant fiber which is generally resistant to mold,mildew, and other problems inherent to natural fibers. The polyesterfiber further provides strength and abrasion resistance and lowers thecost of material. Therefore, it is ideal for use in textiles and othercommercial applications, such as for use in fabrics for apparel, homefurnishings and carpets.

Further, the polyester polymer of the invention may be used with anothersynthetic or natural polymer to form heterogenous fiber, therebyproviding a fiber with improved properties. The heterogeneous fiber maybe formed in any suitable manner, such as side-by-side, sheath-core, andmatrix designs, as is known within the art.

A further specific aspect of the present invention includesbiodegradable shaped foamed articles produced from the sulfonatedaliphatic-aromatic copolyesters which incorporate isosorbide.

The polyesters of the present invention may be readily foamed by a widevariety of methods known in the art. These include the injection of aninert gas such as nitrogen or carbon dioxide into the melt duringextrusion or molding operations. Alternatively, inert hydrocarbon gasessuch as methane, ethane, propane, butane, and pentane, orchlorofluorocarobons, hydrochlorofluorocarbons, hydrofluorocarbons, andthe like may be used. Another method involves the dry blending ofchemical blowing agents with the polyester and then extruding or moldingthe compositions to provide foamed articles. During the extrusion ormolding operation, an inert gas such as nitrogen is released from theblowing agents and provides the foaming action. Typical blowing agentsinclude azodicaronamide, hydrazocarbonamide,dinitrosopentamethylenetetramine, p-toluenesulfonylhydrazodicarboxylate, 5-phenyl-3,6-dihydro-1,3,4-oxa-diazin-2-one,sodium borohydride, sodium bicarbonate, 5-phenyltetrazole,p,p′-oxybis(benzenesulfonylhydrazide) and the like. Still another methodinvolves the blending of sodium carbonate or sodium bicarbonate with oneportion of the polyester pellets, blending of an organic acid, such ascitric acid, with another portion of the polyester pellets and thenblending of the two types of pellets through extrusion or molding atelevated temperatures. Carbon dioxide gas is released from theinteraction of the sodium carbonate and citirc acid to provide thedesired foaming action in the polymeric melt.

It is often desirable that the foamable polyester compositionsincorporate nucleation agents to create sites for bubble initiation,influence the cell size of the foamed sheet or object and to hasten thesoldification of the as foamed article. Examples of said nucleationagents include sodium acetate, talc, titanium dioxide, polyolefinmaterials such as polyethylene, polypropylene, and the like.

As described above, the foamable polyester compositions may include awide variety of additives, fillers, or be blended with other materials.For biodegradable foams, the addition of cellulose, cellulosederivatives, such as chemically modified cellulose, starch, and starchderivatives, such as chemically modified starch and thermoplasticstarch, is especially preferred.

The following Examples are presented to illustrate the preparation andproperties of the sulfonated copolyester polymers of the invention.Comparative Examples are described, i.e., CE1, CE2 and CE3. PropheticExamples E1-E21 describe copolyesters and copolymerization methods ofthe invention as well as the expected biodegradable and mechanicalproperties of the sulfonated copolyesters of the invention.

COMPARATIVE EXAMPLES AND PROPHETIC EXAMPLES

Test Methods

Differential Scanning Calorimetry, (DSC), is performed on a TAInstruments Model Number 2920 machine. Samples are heated under anitrogen atmosphere at a rate of 20° C./minute to 300° C., programmedcooled back to room temperature at a rate of 20° C./minute and thenreheated to 300° C. at a rate of 20° C./minute. The observed sampleglass transition temperature, (Tg), and crystalline melting temperature,(Tm), noted below are from the second heat.

Inherent Viscosity, (IV), is defined in “Preparative Methods of PolymerChemistry”, W. R. Sorenson and T. W. Campbell, 1961, p. 35. It isdetermined at a concentration of 0.5 g./100 mL of a 50:50 weight percenttrifluoroacetic acid:dichloromethane acid solvent system at roomtemperature by a Goodyear R-103B method.

Biodegradation is performed according to the ISO 14855 method:“Determination of the ultimate aerobic biodegradability anddisintegration of plastic materials under controlled compostingconditions—Method by analysis of evolved carbon”. This test involvedinjecting an inoculum consisting of a stabilized and mature compostderived from the organic fraction of municipal solid waste with groundpowder of the polymer to be tested, composting under standard conditionsat an incubation temperature controlled at 58° C.±2° C. The test isconducted with one polymer sample. The carbon dioxide evolved is used todetermine the extent of biodegradation.

Comparative Example CE1

To a 200 gallon autoclave is charged dimethyl terephthalate, (126.16pounds), ethylene glycol, (78.0 pounds), manganese(II) acetatetetrahydrate, (37.65 grams), and antimony(III) trioxide, (13.6 grams).The autoclave is purged three times with nitrogen and heated to 245° C.over 4.5 hours with stirring. Over this heating cycle, over 20,000 gramsof distillate is recovered. With continued heating and stirring, vacuumis staged onto the autoclave over 1.5 hours. The resulting reactionmixture is stirred at 275° C. under fill vacuum, (pressure equal to orless than 2 mm Hg), for 4 hours. The vacuum is then released and theresulting reaction mixture is extruded out of the autoclave as a ribbon,the polymer ribbon is cooled and chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above.

Comparative Example CE2

To a 200 gallon autoclave is charged dimethyl terephthalate, (126.16pounds), isosorbide, (9.5 pounds), ethylene glycol, (73.4 pounds),manganese(II) acetate tetrahydrate, (37.65 grams), and antimony(III)trioxide, (13.6 grams). The autoclave is purged three times withnitrogen and heated to 245° C. over 4.5 hours with stirring. Over thisheating cycle, over 20,000 grams of distillate is recovered. Withcontinued heating and stirring, vacuum is staged onto the autoclave over1.5 hours. The resulting reaction mixture is stirred at 275° C. underfull vacuum, (pressure equal to or less than 2 mm Hg), for 4 hours. Thevacuum is then released and the resulting reaction mixture is extrudedout of the autoclave as a ribbon, the polymer ribbon is cooled andchopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toessentially incorporate 5 mole percent isosorbide, (based on totalglycols). This indicates that 50 percent of the added isosorbide isincorporated within the polymer.

The above prepared polymer is ground to powder and subjected to a Asbiodegradation test as detailed above.

Example 1

To a 200 gallon autoclave is charged dimethyl terephthalate (98.4pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl succinate (19.0 pounds), isosorbide (9.5 pounds), ethyleneglycol (73.4 pounds), manganese(II) acetate tetrahydrate (37.65 grams),and antimony(III) trioxide (13.6 grams). The autoclave is purged threetimes with nitrogen and heated to 245° C. over 4.5 hours with stirring.Over this heating cycle, over 20,000 grams of distillate is recovered.With continued heating and stirring, vacuum is staged onto the autoclaveover 1.5 hours. The resulting reaction mixture is stirred at 275° C.under full vacuum, (pressure equal to or less than 2 mm Hg), for 4hours. The vacuum is then released and the resulting reaction mixture isextruded out of the autoclave as a ribbon, the polymer ribbon is cooledand chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 5 mole percent isosorbide, (based on total glycols) and 20mole percent succinate, (based on total diacids). This indicates that 50percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2.

Example 2

To a 200 gallon autoclave is charged dimethyl terephthalate (98.4pounds), dimethyl 5-sulfoisophthalate sodium salt (3.8 pounds), dimethylglutarate (20.8 pounds), isosorbide (9.5 pounds), ethylene glycol (73.4pounds), manganese(II) acetate tetrahydrate (37.65 grams), andantimony(III) trioxide (13.6 grams). The autoclave is purged three timeswith nitrogen and heated to 245° C. over 4.5 hours with stirring. Overthis heating cycle, over 20,000 grams of distillate is recovered. Withcontinued heating and stirring, vacuum is staged onto the autoclave over1.5 hours. The resulting reaction mixture is stirred at 275° C. underfull vacuum, (pressure equal to or less than 2 mm Hg), for 4 hours. Thevacuum is then released and the resulting reaction mixture is extrudedout of the autoclave as a ribbon, the polymer ribbon is cooled andchopped.

The polymer is tested for inherent viscosity, as described above and isexpected to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 5 mole percent isosorbide, (based on total glycols) and 20mole percent glutarate, (based on total diacids). This indicates that 50percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2

Example 3

To a 200 gallon autoclave is charged dimethyl terephthalate (98.4pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (22.6 pounds), isosorbide (9.5 pounds), ethylene glycol(73.4 pounds), manganese(II) acetate tetrahydrate (37.65 grams), andantimony(II) trioxide, (13.6 grams). The autoclave is purged three timeswith nitrogen and heated to 245° C. over 4.5 hours with stirring. Overthis heating cycle, over 20,000 grams of distillate is recovered. Withcontinued heating and stirring, vacuum is staged onto the autoclave over1.5 hours. The resulting reaction mixture is stirred at 275° C. underfull vacuum, (pressure equal to or less than 2 mm Hg), for 4 hours. Thevacuum is then released and the resulting reaction mixture is extrudedout of the autoclave as a ribbon. The polymer ribbon is cooled andchopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g. This polymer is tested forglass transition temperature by the above mentioned DSC test.

The polymer is analyzed for composition with proton NMR and found toincorporate 5 mole percent isosorbide, (based on total glycols) and 20mole percent adipate, eased on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2

Comparative Example CE3

To a 200 gallon autoclave is charged dimethyl adipate (113.2 pounds),isosorbide (9.5 pounds), ethylene glycol (73.4 pounds), manganese(II)acetate tetrahydrate (37.65 grams), and antimony(II) trioxide (13.6grams). The autoclave is purged three times with nitrogen and heated to245° C. over 4.5 hours with stirring. Over this heating cycle, over20,000 grams of distillate is recovered. With continued heating andstirring, vacuum is staged onto the autoclave over 1.5 hours. Theresulting reaction mixture is stirred at 275° C. under full vacuum,(pressure equal to or less than 2 mm Hg), for 4 hours. The vacuum isthen released and the resulting reaction mixture is extruded out of theautoclave as a ribbon, the polymer ribbon is cooled and chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater t 0.35 dL/g. This polymer is tested forglass transition temperature (Tg) by the above mentioned DSC test. Theproduct from Comparative Example CE 3 is found to have a Tgsignificantly below the Tg found for the product from Example 3.

The polymer is analyzed for composition with proton NMR and found toincorporate 5 mole percent isosorbide, (based on total glycols). Thisindicates that 50 percent of the added isosorbide is incorporated withinthe polymer.

Comparative Example CE4

To a 200 gallon autoclave is charged dimethyl terephthalate (98.4pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (22.6 pounds), ethylene glycol, (81.1 pounds),manganese(II) acetate tetrahydrate, (37.65 grams), and antimony(III)trioxide, (13.6 grams). The autoclave is purged three times withnitrogen and heated to 245° C. over 4.5 hours with stirring. Over thisheating cycle, over 20,000 grams of distillate is recovered. Withcontinued heating and stirring, vacuum is staged onto the autoclave over1.5 hours. The resulting reaction mixture is stirred at 275° C. underfull vacuum, (pressure equal to or less than 2 mm Hg), for 4 hours. Thevacuum is then released and the resulting reaction mixture is extrudedout of the autoclave as a ribbon, the polymer ribbon is cooled andchopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g. This polymer is tested forglass transition temperature by the above mentioned DSC test. Theproduct from Comparative Example CE4 is found to have a Tg significantlybelow the Tg found for the product from Example 3.

The polymer is analyzed for composition with proton NMR and found toincorporate 20 mole percent adipate, (based on total diacids).

Example 4

To a 200 gallon autoclave is charged dimethyl terephthalate (98.4pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (22.6 pounds), isosorbide (19.0 pounds), ethyleneglycol (61.3 pounds), manganese(II) acetate tetrahydrate (37.65 grams),and antimony(III) trioxide, (13.6 grams). The autoclave is purged threetimes with nitrogen and heated to 245° C. over 4.5 hours with stirring.Over this heating cycle, over 20,000 grams of distillate is recovered.With continued heating and stirring, vacuum is staged onto the autoclaveover 1.5 hours. The resulting reaction mixture is stirred at 275° C.under full vacuum, (pressure equal to or less than 2 mm Hg), for 4hours. The vacuum is then released and the resulting reaction mixture isextruded out of the autoclave as a ribbon, the polymer ribbon is cooledand chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 10 mole percent isosorbide, (based on total glycols) and 20mole percent adipate, (based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2.

Example 5

To a 200 gallon autoclave is charged dimethyl terephthalate (98.4pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (22.6 pounds), isosorbide (28.5 pounds), ethyleneglycol (53.6 pounds), manganese(II) acetate tetrahydrate (37.65 grams),and antimony(III) trioxide (13.6 grams). The autoclave is purged threetimes with nitrogen and heated to 245° C. over 4.5 hours with stirring.Over this heating cycle, over 20,000 grams of distillate is recovered.With continued heating and stirring, vacuum is staged onto the autoclaveover 1.5 hours. The resulting reaction mixture is stirred at 275° C.under full vacuum, (pressure equal to or less than 2 mm Hg), for 4hours. The vacuum is then released and the resulting reaction mixture isextruded out of the autoclave as a ribbon, the polymer ribbon is cooledand chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 15 mole percent isosorbide, (based on total glycols) and 20mole percent adipate, (based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2.

Example 6

To a 200 gallon autoclave is charged dimethyl terephthalate (98.4pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (22.6 pounds), isosorbide (38.0 pounds), ethyleneglycol (46.0 pounds), manganese(II) acetate tetrahydrate, (37.65 grams),and antimony(III) trioxide (13.6 grams). The autoclave is purged threetimes with nitrogen and heated to 245° C. over 4.5 hours with stirring.Over this heating cycle, over 20,000 grams of distillate is recovered.With continued heating and stirring, vacuum is staged onto the autoclaveover 1.5 hours. The resulting reaction mixture is stirred at 275° C.under full vacuum, (pressure equal to or less than 2 mm Hg), for 4hours. The vacuum is then released and the resulting reaction mixture isextruded out of the autoclave as a ribbon, the polymer ribbon is cooledand chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 20 mole percent isosorbide, (based on total glycols) and 20mole percent adipate, (based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2.

Example 7

To a 200 gallon autoclave is charged dimethyl terephthalate (98.1pounds), dim ethyl 5-sulfoisophthalate, sodium salt, (3.8 pounds),dimethyl succinate (19.0 pounds), trimethyl 1,2,4-benzenetricarboxylate(0.4 pounds), isosorbide (9.5 pounds), ethylene glycol (73.4 pounds),manganese(II) acetate tetrahydrate, (37.65 grams), and antimony(III)trioxide, (13.6 grams). The autoclave is purged three times withnitrogen and heated to 245° C. over 4.5 hours with stirring. Over thisheating cycle, over 20,000 grams of distillate is recovered. Withcontinued heating and stirring, vacuum is staged onto the autoclave over1.5 hours. The resulting reaction mixture is stirred at 275 C. underfull vacuum, (pressure equal to or less than 2 mm Hg), for 4 hours. Thevacuum is then released and the resulting reaction mixture is extrudedout of the autoclave as a ribbon, the polymer ribbon is cooled andchopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 5 mole percent isosorbide, (based on total glycols) and 20mole percent succinate, (based on total diacids). This would suggestthat 50 percent of the added isosorbide is incorporated within thepolymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2.

Example 8

To a 200 gallon autoclave is charged dimethyl terephthalate (111.0pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (11.3 pounds), isosorbide (19.0 pounds), ethyleneglycol (61.3 pounds), manganese(II) acetate tetrahydrate, (37.65 grams),and antimony(III) trioxide (13.6 grams). The autoclave is purged threetimes with nitrogen and heated to 245° C. over 4.5 hours with stirring.Over this heating cycle, over 20,000 grams of distillate is recovered.With continued heating and stirring, vacuum is staged onto the autoclaveover 1.5 hours. The resulting reaction mixture is stirred at 275° C.under full vacuum, (pressure equal to or less than 2 mm Hg), for 4hours. The vacuum is then released and the resulting reaction mixture isextruded out of the autoclave as a ribbon, the polymer ribbon is cooledand chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 10 mole percent isosorbide, (based on total glycols) and 10mole percent adipate, (based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2.

Example 9

To a 200 gallon autoclave is charged dimethyl terephthalate (85.8pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (34.0 pounds), isosorbide (19.0 pounds), ethyleneglycol (61.3 pounds), manganese(II) acetate tetrahydrate (37.65 grams),and antimony(III) trioxide, (13.6 grams). The autoclave is purged threetimes with nitrogen and heated to 245° C. over 4.5 hours with stirring.Over this heating cycle, over 20,000 grams of distillate is recovered.With continued heating and stirring, vacuum is staged onto the autoclaveover 1.5 hours. The resulting reaction mixture is stirred at 275° C.under full vacuum, (pressure equal to or less than 2 mm Hg), for 4hours. The vacuum is then released and the resulting reaction mixture isextruded out of the autoclave as a ribbon, the polymer ribbon is cooledand chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 10 mole percent isosorbide, (based on total glycols) and 30mole percent adipate, based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2

Example 10

To a 200 gallon autoclave is charged dimethyl terephthalate (73.2pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (45.3 pounds), isosorbide (19.0 pounds), ethyleneglycol (61.3 pounds), manganese(II) acetate tetrahydrate (37.65 grams),and antimony(III) trioxide (13.6 grams). The autoclave is purged threetimes with nitrogen and heated to 245° C. over 4.5 hours with stirring.Over this heating cycle, over 20,000 grams of distillate is recovered.With continued heating and stirring, vacuum is staged onto the autoclaveover 1.5 hours. The resulting reaction mixture is stirred at 275 C underfull vacuum, (pressure equal to or less than 2 mm Hg), for 4 hours. Thevacuum is then released and the resulting reaction mixture is extrudedout of the autoclave as a ribbon, the polymer ribbon is cooled andchopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 10 mole percent isosorbide, (based on total glycols) and 40mole percent adipate, (based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2

Example 11

To a 200 gallon autoclave is charged dimethyl terephthalate (60.6pounds), dim ethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (56.6 pounds), isosorbide (19.0 pounds), ethyleneglycol (61.3 pounds), manganese(II) acetate tetrahydrate (37.65 grams),and antimony(III) trioxide (13.6 grams). The autoclave is purged threetimes with nitrogen and heated to 245° C. over 4.5 hours with stirring.Over this heating cycle, over 20,000 grams of distillate is recovered.With continued heating and stirring, vacuum is staged onto the autoclaveover 1.5 hours. The resulting reaction mixture is stirred at 275° C.under full vacuum, (pressure equal to or less than 2 mm Hg), for 4hours. The vacuum is then released and the resulting reaction mixture isextruded out of the autoclave as a ribbon, the polymer ribbon is cooledand chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toessentially incorporate 10 mole percent isosorbide, (based on totalglycols) and 50 mole percent adipate, (based on total diacids). Thiswould suggest that 50 percent of the added isosorbide is incorporatedwithin the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2.

Example 12

To a 200 gallon autoclave is charged dimethyl terephthalate (73.8pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (22.6 pounds), isophthalic acid (21.0 pounds),isosorbide (19.0 pounds), ethylene glycol (61.3 pounds), manganese(II)acetate tetrahydrate (37.65 grams), and antimony(III) trioxide (13.6grams). The autoclave is purged three times with nitrogen and heated to245° C. over 4.5 hours with stirring. Over this heating cycle, over20,000 grams of distillate is recovered. With continued heating andstirring, vacuum is staged onto the autoclave over 1.5 hours. Theresulting reaction mixture is stirred at 275° C. under fill vacuum,(pressure equal to or less than 2 mm Hg), for 4 hours. The vacuum isthen released and the resulting reaction mixture is extruded out of theautoclave as a ribbon, the polymer ribbon is cooled and chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 10 mole percent isosorbide, (based on total glycols) and 20mole percent adipate, (based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2.

1.1 grams of this polymer is dissolved in 10.0 grams of tetrahydrofuranat room temperature. After mixing for 4 hours at room temperature, aclear solution is obtained. The solution is poured into a 2-inchdiameter aluminum pan and allowed to dry at room temperature overnight.The resulting film is clear and pliable.

Example 13

To a 5 gallon autoclave is charged terephthalic acid (14.9 pounds),dimethyl 5-sulfoisophthalate, sodium salt (0.7 pounds), adipic acid (3.4pounds), isosorbide (1.7 pounds), ethylene glycol (13.5 pounds),cobalt(II) acetate tetrahydrate (1.83 grams), and antimony(III) trioxide(3.10 grams). The polymerization autoclave is equipped with a fractionaldistillation column and a stirrer. The autoclave is purged tree timeswith nitrogen, closed under 50 psig of nitrogen pressure and heated to265° C. over 5 hours with stirring. The pressure rises to 70 psig duringthis time, as esterification takes place. At the end of this timeperiod, the pressure is vented back to psig. Water and ethylene glycoldistill from the autoclave. The temperature is maintained at 265° C.Within an hour, the contents of the autoclave are a clear, viscous melt.The excess pressure in the autoclave is then vented. A solution ofethylene glycol and polyphoshoric acid (3.45 weight percent phosphorous)is pumped into the autoclave. With continued heating and stirring,vacuum is staged onto the autoclave. The autoclave is then heated to275° C. The resulting reaction mixture is stirred at 275 C under fullvacuum, (pressure equal to or less than 2 mm Hg), for 4 hours. Thevacuum is then released and the resulting reaction mixture is extrudedout of the autoclave as a ribbon, the polymer ribbon is cooled andchopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g. This polymer is tested forglass transition temperature by the above mentioned DSC test.

The polymer is analyzed for composition with proton NMR and found toincorporate 5 mole percent isosorbide, (based on total glycols) and 20mole percent adipate, (based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention is expected to have a biodegradation rate at least twice thatof the polymers from Comparative Example 1 and Comparative Example 2.

Example 14

To a 200 gallon autoclave is charged dimethyl2,6-naphthalenedicarboxylate (92.1 pounds), dimethyl5-sulfoisophthalate, sodium salt (3.8 pounds), dimethyl adipate (45.3pounds), isosorbide (19.0 pounds), ethylene glycol (61.3 pounds),manganese(II) acetate tetrahydrate (37.65 grams), and antimony(III)trioxide, (13.6 grams). The autoclave is purged three times withnitrogen and heated to 245° C. over 4.5 hours with stirring. Over thisheating cycle, over 20,000 grams of distillate is recovered. Withcontinued heating and stirring, vacuum is staged onto the autoclave over1.5 hours. The resulting reaction mixture is stirred at 275° C. underfull vacuum, (pressure equal to or less than 2 mm Hg), for 4 hours. Thevacuum is then released and the resulting reaction mixture is extrudedout of the autoclave as a ribbon, the polymer ribbon is cooled andchopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 10 mole percent isosorbide, (based on total glycols) and 40mole percent adipate, (based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention was found to biodegrade.

Example 15

To a 200 gallon autoclave is charged dimethyl terephthalate (60.6pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (56.6 pounds), isosorbide (19.0 pounds), 1,4-butanediol(75.0 pounds), and titanium(IV) isopropoxide, (19.57 grams). Theautoclave is purged three times with nitrogen and heated to 245° C. over4.5 hours with stirring. Over this heating cycle, over 20,000 grams ofdistillate is recovered. With continued heating and stirring, vacuum isstaged onto the autoclave over 1.5 hours. The resulting reaction mixtureis stirred at _(255°) C. under fall vacuum, (pressure equal to or lessthan 2 mm Hg), for 4 hours. The vacuum is then released and theresulting reaction mixture is extruded out of the autoclave as a ribbon,the polymer ribbon is cooled and chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 10 mole percent isosorbide, (based on total glycols) and 50mole percent adipate, (based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention was found to biodegrade.

Example 16

To a 200 gallon autoclave is charged dimethyl terephthalate (60.6pounds), dimethyl 5-sulfoisophthalate, sodium salt (3.8 pounds),dimethyl adipate (56.6 pounds), isosorbide (19.0 pounds),1,3-propanediol (63.3 pounds), and titanium(IV) isopropoxide (19.57grams). The autoclave is purged three times with nitrogen and heated to245° C. over 4.5 hours with stirring. Over this heating cycle, over20,000 grams of distillate is recovered. With continued heating andstirring, vacuum is staged onto the autoclave over 1.5 hours. Theresulting reaction mixture is stirred at 255° C. under full vacuum,(pressure equal to or less than 2 mm Hg), for 4 hours. The vacuum isthen released and the resulting reaction mixture is extruded out of theautoclave as a ribbon, the polymer ribbon is cooled and chopped.

The polymer is tested for inherent viscosity, as described above and isfound to have an IV greater than 0.35 dL/g.

The polymer is analyzed for composition with proton NMR and found toincorporate 10 mole percent isosorbide, (based on total glycols) and 50mole percent adipate, (based on total diacids). This would suggest that50 percent of the added isosorbide is incorporated within the polymer.

The above prepared polymer is ground to powder and subjected to abiodegradation test as detailed above. This copolyester of the presentinvention was found to biodegrade.

Example 17

The polymer of the present invention produced in Example 1, above, isextruded as a film using a Killion PL 100 Film extrusion line. Theprocessing conditions are as follows:

Extruder Barrel Temperature zone l 190° C. zone 2 230° C. zone 3 250° C.zone 4 250° C. Clamp ring temperature 250° C. Adaptor temperature(inlet) 240° C. Melt pump temperature 240° C. Melt pump rpm 10Throughput 3 lb./hr. Adaptor temperature (outlet) 230° C. Extruder meltpressure ˜1500 psi Die adaptor temperature 230° C. Die temperature 230°C. Die Lip temperature 230° C. Die gap 0.25 mm (10 mil) Die size 4-inchCasting temperature 50° C. Casting speed 5 & 3 m/min. Filter size 25microns

The film exiting the die is 4 inches wide and 0.10 mm (4 mils) thick.

The extruded film is stretched uniaxially or biaxially using a modifiedBruckner Stretching Frame (Bruckner, Siegsdorf, Germany). The sample isinserted with the machine direction (MD) on the Y axis of the machine.Draw speed is 1.50 in./sec. Typical machine settings include; Plaquepreheat temp=110° C., Shutter Close Temperature=115° C., and Emittertemperature=600° C. When a Draw ratio X (X 100%)=1 and a Draw ratio Y (X100%)=2 is performed on the as extruded film, the film modulus andelongating at break are both significantly improved over that found forthe unstretched film.

Both the as extruded film and the oriented film produced from thesulfonated aliphatic, aromatic copolyester which incorporates isosorbideof the present invention are found to have enhanced heat deflectiontemperature (HDT) and film sag temperature over similar films producedfrom the aliphatic isosorbide of the art. Both the as extruded film andthe oriented film produced from the copolyester of the present inventionare found to have at least twice the biodegradation rate found fromsimilar films produced from the aromatic isosorbide polyesters of theart.

Example 18

The materials produced in Examples 1, 2, or 3, above, are injectionmolded into discs (thickness ⅛ inch, diameter 4 inches) and tensilebars. A Boy 30M (Boy Gmbh, Fernthalr, Germany) was used to injectionmold the parts. The conditions used are as follows:

Barrel temperature 250° C. Mold temperature 50° C. Screw speed 210 rpmInjection speed 100% Injection pressure 13 bar Hold pressure 12 bar Backpressure 3 bar Injection time 2 seconds Cooling time 25 seconds

The as molded tensile bars produced from the copolyester of the presentinvention are found the have enhanced tensile strength over similartensile bars produced from the aliphatic isosorbide of the art. The asmolded discs produced from the copolyester of the present invention areexpected to have at least twice the biodegradation rate found fromsimilar discs produced from the aromatic isosorbide polyesters of theart.

Example 19

The polymer produced in Example 3, above, is used to produce a 14 milthick sheet by extrusion using a film/sheet pilot line made by EganMachinery (Somerville, N.J.). The conditions for extrusion are asfollows:

Extruder barrel temperatures Zone 1 245° C. Zone 2 245° C. Zone 3 245°C. Zone 4 245° C. Zone 5 265° C. Zone 6 265° C. Melt line temp.  50° C.Die temp. 260° C. Roller 1  25° C. Roller2  25° C. Roller 3  20° C.

The sheet is trimmed to 6 to 7 inches wide and approximately 11 incheslong. After heating in a rectangular retaining bracket at 165° C. in aconvection oven until softening takes place, the sheet is vacuumthermoformed into 1½ inch and 2 inch deep room temperature molds todemonstrate ability to thermoform. The obtained containers are opticallyclear and mechanically robust.

Example 20

The polymers of the present invention produced in Examples 2 and 3,above, are made into 460 mL jars on a commercial Nissei ASB100DHInjection Single Blow stretch-blow molding unit using a one-stagestretch-blow molding process, and using a 132.5 mm rod for the stretch.The polymer is injection molded at a melt temperature of 240° C. to makea preform, which is then subjected to the stretch-blow molding processat 90° C. in the same equipment without complete cooling.

The jars produced from the copolyesters of the present invention arefound the have enhanced thermal properties, as seen through glasstransition temperature as measured by DSC, heat deflection temperature(HDT) and sag temperature over similar jars produced from the aliphaticisosorbide of the art. The jars produced from the copolyesters of thepresent invention are expected to have at least twice the biodegradationrate found from similar jars produced from the aromatic isosorbidepolyesters of the art.

Example 21

The polymer of the present invention produced in Example 1, above, isground and dried at 130° C. overnight in a vacuum. Rods are made fromthe polymer by first placing it in a mold which is then heated undergentle pressure from a plunger. The pressure is provided by a hydraulicpress. When the polymer began to soften, more pressure (500-1000lbs/in²) is applied to compress the polymer into a hard rod. The ingressof moisture is reduced by encasing the equipment in a Lucite® box whichis continuously purged by a flow of dry nitrogen.

Spinning is immediately carried out on a single filament spinningmachine. The polymer is rod form is melted by pressing it against aheated “grid” which is conical in shape with a hole at the apex. Themachine temperatures are slowly raised until the melted polymer startsto flow through this hole. In the present example, this occurs atapproximately 250° C. The polymer is then filtered through a bed of80/120 shattered metal, and finally emerges from the single holespinneret capillary, 0.020 inch in diameter and 0.030 inch long. Thetroughput is 0.30 grams per minute (gpm), and the fiber, which is to bedrawn, is taken up at 50 meters per minute (mpm). These condition arefound to give low orientation single filaments of about 70 deneir perfilament (dpf). A temperature scan is made to produce the optimum spunfiber for subsequent drawing. A fiber sample is also made at the maximumtake up speed possible in order to obtain a feel for the draw down andto measure the spun fiber properties.

Single filament drawing is performed on modular draw units with hotshoes between each roll. The fiber is drawn in two stages using thesecond stage to develop the maximum fiber tenacity and crystallinity. Inthis way, a single filament is collected and small samples cut from thelast roll. A sample is tested for its thermal properties by the abovementioned DSC method and for tensile properties using ASTM test methodD3822.

The fiber produced from the copolyesters of the present invention arefound to have enhanced thermal properties, as demonstrated through theglass transiton temperature as measured by the above mention DSC method,than found for comparable fiber produced from the aliphatic isosorbidepolyesters of the art and the sulfonated aliphatic, aromaticcopolyesters of the art which do not incorporate isosorbide. The fiberproduced from the polymer of the present invention is expected to havean improved biodegradation rate than found for comparable fiber producedfrom aromatic isosorbide polyesters of the art.

While the invention has been described in the preceding Examples, thereis no intent to limit the scope of the invention to the scope of thoseExample as one skilled in the art will understand that the invention isapplicable to other combinations and materials not taught herein byspecific example.

What is claimed is:
 1. A sulfonated copolyester comprising thepolymerization product of: (a) one or more aromatic dicarboxylic acidsor an ester thereof; (b) one or more aliphatic dicarboxylic acids or anester thereof; (c) one or more sulfonated compound; and (d) isosorbide.2. A copolyester as claimed in claim 1, comprising about 20 to about 98mole percent of (a) based on total dicarboxylic acid in the copolyester,about 2 to about 80 mole percent of (b) based on total dicarboxylic acidin the copolyester, about 0.1 to about 10.0 mole percent of (c) based ontotal glycol or total dicarboxylic acid in the copolyester, and about 1to about 100 mole percent of (d) based on total glycols in thecopolyester.
 3. A copolyester as claimed in claim 1, further formed froma dihydric alcohol.
 4. A copolyester as claimed in claim 1, furtherformed from a polyfunctional chain branching agent.
 5. A copolyester asclaimed in claim 1, wherein the sulfonated compound comprises asulfonated mono or dicarboxylic acid, or an ester or metal salt thereof.6. A copolyester as claimed in claim 1, which has an inherent viscosityof at least about 0.15 dL/g.
 7. A copolyester as claimed in claim 1,which has a rate of biodegradability at least twice that of acopolyester formed from the corresponding amount and type of said (a),(c), and (d).
 8. A copolyester as claimed in claim 1, wherein thearomatic dicarboxylic acid or ester (a) is selected from the groupconsisting of terephthalic acid, dimethyl terephthalate, isophthalicacid, dimethyl isophthalate, 2,6-naphthalene dicarboxylic acid,dimethyl-2,6-naphthalate, and mixtures of two or more thereof.
 9. Acopolyester as claimed in claim 1, wherein the aliphatic dicarboxylicacid or ester is selected from the group consisting of succinic acid,dimethyl succinate, glutaric acid, dimethyl glutarate, adipic acid,dimethyl adipate, dimer acid, and mixtures of two or more thereof.
 10. Acopolyester as claimed in claim 3, wherein the dihydric alcohol isselected from the group consisting of ethylene glycol, 1,3-propanediol,1,4-butanediol, poly(ethylene ether) glycols, and a mixture of two ormore thereof.
 11. A copolyester as claimed in claim 4, wherein thepolyfunctional chain branching agent comprises a polycarboxylic acid orester thereof or a polyhydric alcohol.
 12. A copolyester as claimed inclaim 4, wherein the polyfunctional chain branching agent is selectedfrom the group consisting of trimellitic acid, pyromelletic anhydrideand esters thereof, pentaerythritol and mixtures thereof.
 13. Acopolyester as claimed in claim 1, wherein the sulfonated compound isselected from the group consisting of sulfosuccinic acid, 3-sulfobenzoicacid, 4-sulfobenzoic acid, 5-sulfosalicylic acid, sulfophthalic acid,sulfoterephthalic acid, and 5-sulfoisophthalic acid; or an ester or saltthereof.
 14. A copolyester as claimed in claim 1, wherein the sulfonatedcompound is in the form of a metal salt.
 15. A method of improving thebiodegradability and thermal properties of polyester, comprising formingthe polyester from (a) one or more aromatic dicarboxylic acids or anester thereof; (b) one or more aliphatic dicarboxylic acids or an esterthereof; (c) one or more sulfonated compound; and (d) isosorbide.
 16. Amethod of preparing a copolymer as claimed in claim 1, comprising meltpolymerizing components (a), (b), (c), and (d).
 17. A shaped articleformed at least in part from a copolyester as claimed in claim
 1. 18. Afilm or sheet formed at least in part from a copolyester of claim
 1. 19.An injection molded, compression molded, blow molded, or foamed articleformed at least in part from a copolyester of claim
 1. 20. A fiberformed at least in part from a copolyester of claim 1.